fix KV API to unified format, and test

vitest.config.ts

@@ -0,0 +1,17 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+    test: {
+        globals: true,
+        environment: 'node',
+        include: ['test/**/*.test.ts'],
+        testTimeout: 30000, // 30s timeout for FFprobe tests
+        hookTimeout: 60000, // 60s for setup/teardown
+        coverage: {
+            provider: 'v8',
+            reporter: ['text', 'json', 'html'],
+            include: ['src/**/*.ts'],
+            exclude: ['src/types.ts'],
+        },
+    },
+});